HIGH STRENGTH HOT-DIP GALVANIZED STEEL SHEET EXCELLENT IN ELONGATION AND HOLE EXPANSIBILITY AND PRODUCTION METHOD THEREFOR

Title:

HIGH STRENGTH HOT-DIP GALVANIZED STEEL SHEET EXCELLENT IN ELONGATION AND HOLE EXPANSIBILITY AND PRODUCTION METHOD THEREFOR

Document Type and Number:

Japanese Patent JP2017053009

Kind Code:

A

Abstract:

PROBLEM TO BE SOLVED: To increase elongation and hole expansibility of a high strength hot-dip galvanized steel sheet with a strength of 590 MPa or more.SOLUTION: The high strength hot-dip galvanized steel sheet excellent in elongation and hole expansibility is provided that has a component composition containing, by mass%, C:0.07% to 0.22%, Si:0.005% to 1.00%, Mn:1.50% to 2.80%, P:0.001% to 0.100%, S:0.0005% to 0.010%, N:0.0005% to 0.010%, Al:0.02% to 1.00% and the balance Fe with inevitable impurities, and that has (i) a metallographic structure which consists of ferrite of 15% or more and less than 50% by area ratio, retained austenite of less than 5% by area ratio, martensite of 30% to 72% by area ratio, pearlite of 5% or less by area ratio and the balance bainite and (ii) in the metallographic structure, ferrite mass with a thickness in a sheet thickness direction of 20 μm or less is 50% or more based on total number of ferrite mass in the metallic structure.SELECTED DRAWING: Figure 1

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Inventors:

OKAMOTO TSUTOMU
SANO KOICHI
YAMAGUCHI YUJI

Application Number:

JP2015178857A

Publication Date:

March 16, 2017

Filing Date:

September 10, 2015

Export Citation:

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Assignee:

NIPPON STEEL & SUMITOMO METAL CORP

International Classes:

C22C38/00; C21D9/46; C22C38/06; C22C38/38

Domestic Patent References:

JP2008280608A	2008-11-20
JP2010275628A	2010-12-09
JP2012219328A	2012-11-12
JP2010013700A	2010-01-21

Foreign References:

WO2013047820A1	2013-04-04
WO2012081666A1	2012-06-21
WO2011087057A1	2011-07-21
EP1154028A1	2001-11-14

Attorney, Agent or Firm:

Atsushi Aoki
Takashi Ishida
Tetsuji Koga
Hiroshi Kamematsu
Fukuchi Ritsuo
Nakamura Asayuki
Hideo Tokunaga

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